1. Field of the Invention
The present invention relates to a fuel-cell evaluation equipment, and more particularly to a fuel-cell evaluation equipment adapted to control conditions of gas to be supplied to the fuel cell.
2. Description of the Related Art
Recently, in order to develop a fuel cell applicable for use as a power source for devices such as cars with sharp load fluctuations or severe temperature fluctuations in use environment, it is desired to provide a fuel-cell evaluation equipment that is able to control conditions such as flow rate, temperature, and humidity of gas to be supplied to the fuel cell more largely and accurately.
Thus, to achieve the object, test equipment provided with a gas supply unit for evaluation tests as disclosed in JP 2004-273222A has been employed on a performance test for a fuel cell in the related art. The gas supply unit for an evaluation test disclosed in JP 2004-273222A heats or humidifies gas by means of so-called bubbling, whereby the gas is immersed in the water stored in a predetermined reservoir, a gas consisting mainly of hydrogen or oxygen that is used as active materials, thereby enabling to control temperature or humidity of gas to be supplied to a fuel cell.
According to the evaluation equipment of this structure, the evaluation test for a fuel cell is performed under various modifications of conditions such as an output condition or an operating atmospheric temperature.
However, the foregoing conventional fuel-cell evaluation equipment has such a problem that considerable changes of control range of parameter, which is a test condition for a fuel cell, renders the conditions such as the temperature of gas to be supplied to the fuel cell unstable and results in lowering the accuracy of the evaluation test.
Further, to make gas supply to a fuel cell be wildly changed, it is necessary to make a duct diameter for gas supply large so as to be able to supply a high flow of gas. In this structure, if and when the evaluation test is carried out with extremely small gas supply to a fuel cell, the gas remains in the duct for gas supply for long periods of time, resulting in a problem that large divergence of the temperature of gas supply from that of the testing conditions.
Still further, when a heater for heating gas employs one capable of heating a high flow rate of gas, the temperature of supplied gas with extremely small gas supply to a fuel cell is not well controlled, resulting in a problem that the accuracy of the evaluation test is lowered.